The present invention relates to a machine for washing articles and more particularly to a machine useful in washing large trays or similar items. Supermarkets, bakeries and delicatessens typically display food products in glass cases with various products placed upon a number of large metal or plastic trays. These large trays are unusually difficult to clean since they will not fit into ordinary automated washing apparatus. The trays must therefore be washed by hand or by special washing apparatus having an access opening and washing chamber which are sufficiently large. Typically, space limitations in bakeries, delicatessens, and supermarkets are rather severe. Therefore, the door arrangement covering the access opening of such special washing apparatus must not obstruct an undue amount of space in front of the washer when the device is being loaded with trays. A downwardly opening door is desirable, though, to provide a platform for supporting a tray rack while the rack is loaded.
An additional problem with washers having a downwardly opening door and a vent opening beneath the door is the splashing of hot washing fluid through the vent opening at the initiation of each washing operation. As one rack of trays is removed and replaced by another in the washing chamber, the hot vapor laden air is replaced by cooler, drier room air. If the door is then closed and the washing cycle initiated, two things occur. First, water is sprayed on all the walls of the washing chamber and runs down the sides in sheets. The sheet of water on the inside of the door would normally drop from the bottom of the door into the bottom of the washing chamber. However, at the beginning of the washing operation, a sudden increase in pressure within the chamber occurs due to the rapid increase in temperature of the air within the chamber when the air is mixed with the hot wash water. This sudden pressure change typically will blow the sheet of water dropping from the bottom of the front door through the vent opening. Attempts to solve this problem by bending the bottom lip of the door inwardly have been unsuccessful since such a lip will interfere with the sliding of a tray rack into and out of the washing chamber.
One approach which could be taken to cover the large access opening required in a device of this type would be to use a single large downwardly opening door. Such a door when in its opened position would interfere with the utilization of space in front of the access opening. Closure mechanisms such as shown in U.S. Pat. No. 1,253,356 to Delaney, issued Jan. 15, 1918 and U.S. Pat. No. 2,288,482 to Plohberger, issued June 30, 1942, while providing large access openings, are not useful with a washing device. This is because a device for washing large items must have spray arms both above and below the washing chamber and such a closure mechanism would interfere with the operation of the upper spray arms.
U.S. Pat. No. 2,860,026 to Long, issued Nov. 11, 1958, shows a double door arrangement which, while allowing a large access opening to be utilized, is unacceptable in a washer environment in that a door does not open downwardly in front of the washer to provide a rack supporting surface for loading and unloading. U.S. Pat. No. 3,655,942 to Tomsic, issued Apr. 11, 1972, does disclose a double door arrangement with one door opening downwardly; however, the two doors are utilized to close the same opening in an oven, the second door being used as a heat shield.
In U.S. Pat. No. 3,049,391 to Meeker et al., issued Aug. 14, 1962, and assigned to the assignee of the present invention, a two-door closure is shown for a washing machine having a vertically enlarged washing chamber. The washer is designed to accommodate large "hotel" trays. The closure disclosed has a lower door panel which is hinged to the lower edge of an upper door panel. The lower door panel moves upwardly with the upper door panel and also swings outwardly to uncover completely the access opening to the washing chamber. While this door arrangement uses a minimum of the space surrounding the washer, it does not provide a surface for supporting a rack during loading and unloading. Separate rack supporting structure must therefore be provided.